N-aryl-n&#39;alkyl-n&#39;arylthio ureas as herbicides

ABSTRACT

Ureas of the formula:   D R A W I N G

United States Patent Brown 1451 Oct. 10, 1972 |54| N-ARYL-N'ALKYL-N'ARYLTHIO FOREIGN PATENTS OR APPLICATIONS UREAS AS HERBICIDES 965,512 7/1964 Great Britain ..260/453 R [72] Inventor: Melancthon S. Brown, Berkeley,

Calif. Primary Examiner-Lewis Gotts Assistant Examiner-G. Hollrah [73] Asslgnee' $23522 Company San Attorney-J. A. Buchanan, Jr., G. F. Magdeburger,

l John Stoner, Jr. and Raymond Owyang [22] Filed: May 28, 1970 [21] Appl. No.: 41,603 [57] ABS CT Ureas of the formula: Related US. Application Data 0 R [63] Continuation-impart of Ser. No. 709,896, Mar. NH-gN 4, I968, abandoned, and a continuation-in-part (Y) of Ser. No. 3,238, Jan. 15, 1970, abandoned, which is a continuation-in-part of Ser. No. w 709,896.

where R is alkyl of one to four carbon atoms, Y 1s 52 us. c1. ..260/453 R, 71/98 habge" ammic number 9 Lee E C1 and Br, alkyl of one to four carbon atoms, alkoxy of [51] Int. Cl ..C07c 119/00 one to four carbon atoms or trifluoromethyl with F Id I h ..2604 3R;7l ,120 [58] o Seam 5 /98 the proviso that when Y 1s alkyl or alkoxy, Y 1s 1n position 2, 4 or 6 of the nucleus, n is 0 or an in- [56] References Clted teger in the range of 1 and 3 inclusive with the UNITED TE NT proviso that when n is 2 or 3 at least one Y is halogen, 8 is halogen of atomic number 9 to 35 or Bauer et a1. of one to about f carbon atoms and a i 3,165,549 l/I965 Mart n et al. ..71/ 0, an integer in the range of 1 and 5 inclusive 3,497,541 2/1970 Martm et al. ..71/120 when Z is halogen, or 1 when Z is alkyl These 3,276,855 10/1966 R1chter ..71/98 ureas are herbicidaL 2,655,445 10/1953 Todd ..71/120 3,309,192 3/1967 Luckenbaugh ..71/120 9 Claims, No Drawings N-ARYL-N'ALKYIIN'ARYL'I'HIO UREAS AS HERBICIDES CROSS REFERENCE TO RELATED APPLICATIONS This application is a continuation-in-part of copending application Ser. No. 709,896, filed Mar. 4, 1968 now abandoned, and a continuation-in-part of copending application Ser. No. 3,238, filed Jan. 15, 1970 now abandoned. Application Ser. No. 3,238 is a continuation-in-part of application Ser. No. 709,896.

FIELD OF INVENTION This invention concerns a novel group of aromatic ureas and their use as herbicides. More particularly it concerns N-aryl-N'-alkyl-N'-arylthio ureas and their use as herbicides.

INVENTION DESCRIPTION The herbicidal ureas of this invention may be represented by the formula:

where R is alkyl of one to about four carbon atoms, Y is halogen of atomic number 9 to 35, Le, F, Cl and Br, alkyl of one to about four carbon atoms, alkoxy of one to about four carbon atoms or trifluoromethyl, with the proviso that when Y is alkyl or alkoxy, it is in position 2, 4 or 6 of the nucleus, n is or an integer in the range of l and 3 inclusive with the proviso that when n is 2 or 3 at least one Y is halogen, Z is halogen of atomic number 9 to 35 or alkyl of one to about four carbon atoms and a is 0, an integer in the range of 1 and inclusive when Z is halogen, or 1 when Z is alkyl. The Ys and Zs wherein n and a are integers greater than 1 may be the same or different.

Because of their exceptional herbicidal activities the compounds wherein R is methyl, a is I, Z is in position 4 of the benzene nucleus and is hydrogen, chlorine or alkyl of one to four carbon atoms and (a) when n is 1, Y is fluorine in position 2 or chlorine in position 4 or (b) when n is 2, one Y is chlorine in position 3 and the other Y is chlorine or bromine in position 4, are preferred. These preferred compounds may be represented by the formulas:

wherein Z is Cl, hydrogen or alkyl of one to four carbon atoms and Y' is chlorine in position 4 or fluorine in position 2, and

wherein Z is as defined previously and Y is Cl or Br. The compounds of formulas 2 and 3 wherein Z is chlorine are particularly preferred.

Examples of ureas represented by formula (1) are: N-m-bromophenyl-N '-propyl-N '-p-bromophenylthio urea, N-o-fluorophenyl-N'butyl-N'-p-chlorophenylthio urea, N-2,6-dichloro-4-methylphenyl-N-methyl- N-p-bromophenylthio urea, N-2-bromo-4-methoxyphenyl-N'-isopropyl-N-4-ethylphenylthio urea, N- 2,4,6-trichlorophenyl-N-butyl-N-2,5-dichlorophenylthio urea, N-2-methyl-3,4-difluorophenyl-N'-methyl- N-p-fluorophenylthio urea, N-p-ethylphenyl-N'- methyl-N-3,4-dibromophenylthio urea, N-p-cumyl-N'- n-butyl-N'm-chlorophenylthio urea, N-p-butylphenyl- N-methyl-N'-pentachlorophenylthio urea, N-o-ethoxyphenyl-N'-methyl-N'-tolylthio urea, N-p-butoxyphenyl-N'-ethyl-N'-p-chlorophenylthio urea, N-2,4,6- tribromophenyl-N-propyl-N-p-cumylthio urea, N-pethylphenyl-N'-butyl-N'-p-butylphenylthio urea, N-pethoxyphenyl-N'-ethyl-N-2,4,6-trichlorophenylthio urea, N-2-chloro-4-butylphenyl-N-methyl-N'-pentabromophenylthio urea, N-4-butoxy- 2,6- difluorophenyl-N'-methyl-N'-3,4-difluorophenylthio urea and N-p-methoxyphenyl-N'-propyl-N'-2,4,6- trifluorophenylthio urea.

The above described ureas may be prepared by reacting a urea with a sulfenyl halide according to the following equation:

wherein X is halogen, preferably chlorine, and Y, R, Z, n and a are as previously defined. This reaction may be carried out in pyridine, dimethyl formamide with or without an acid acceptor or other solvents such as methylene chloride, chloroform, acetonitrile and dimethoxyethane using an acid acceptor. Acid acceptors which may be used with dimethyl formamide and these other solvents are pyridine, alkylpyridines, quinoline and similar heterocyclic bases. Pyridine is a preferred acid acceptor. When pyridine is used alone it acts both as a solvent and acid acceptor. The preferred medium for carrying out this reaction is dimethyl formamide with pyridine as an acid acceptor.

The pressures and temperatures at which the reaction is carried out are not critical. Since the reaction is slightly exothermic, temperatures ranging from ambient to about 60 C. will normally be used. However, lower temperatures or higher temperatures up to the decomposition temperature of the reactants and product may be used. For convenience the pressure will usually be atmospheric or autogenous. The reac tion will normally be complete within 30 minutes to 4 hours.

The urea reactant in the above equation may be prepared in situ or beforehand. Conventional methods such as reacting an amine with an isocyanate may be used to prepare this reactant.

EXAMPLES The following examples illustrate two methods which may be used to prepare the ureas of this invention. These examples are in no way intended to limit the ing. p-chlorophenmixture. The temixture increased slightly during this irred at ambient temperature for 1 time 1 liter of ice water was added to d. The dried solid weighed 39 g. Gas f this solid indicated it -chlorophenylN-methyl-N'-p- This compound melted at ion from mpound melted at Element analyses Melting Cl point,

Found Cale. Found 0.

tie

d was purified by recrystallizat Cale.

indicated, dimethylformamide and l 1.8 g. pyridine were mixed in a vessel at ambient temperature. 26.6 ylsulfenyl chloride was added to this perature of the m 40 5 addition, but it did not exceed 40 C. The combined this mixture was then st hour. After this the mixture to form a solid percipitate. The mixture was filtered and the solid was washed with water and hexane and aird rials ylene llqllld chromographlc analysis 0 Sank was essentially pure N-p chlorophenylthio urea.

id 8596 C. and its sulfur and chlorine analyses were:

Calculated: S: 9.80%; C] benzene Found s- 9 99% and 100 ml. of hexane. The recrystallizedproduct was washed with 50 ml of hexane to ive 21 6 of N- g p benzene and hexane. The purified co chlorophenyl-N -methyl-N -p-chlorophenylth1o urea. 95 98 c Other ureas included. within this invention were prepared using one or more of the methods described above. These compounds are listed in Table I.

TABLE I rwise in a vess vention described .herein. Unless othe percentages are by weight.

A mixture of. 25 g. of N-p-chlorophenyl-N'-methyl urea in 200 g. of pyridine was placed of p-chlorophenylsulfenyl chloride was added to 25 g. of N-p-chlorophenyl-N'-methyl urea, 100 g.

Example 1 mixture. The "combined mixture was stirred for one hour at ambient temperature. At the end of this time the mixture was added to a mixture of 200 g. of concentrated HCl in 1 liter of ice water. The organic mate in the mixture'were extracted with 500 g. of meth chloride. The extract was washed with dilute l-lCl rated NaHCO solution and water, dried and stripped to an orange oil which crystallized slowly. This so] was recrystallized from a mixture of 50 ml Its meltingpoint was 9497 C.

Example 2 Compound L0 2 &L2 0 .0 21 11 l 119 I h I h e a I 2 2 m2 122 2 t a h 1 1 1 99 00 09908000 090 8.1986918 909909008780899 3 .0 ..hejhshuhhj ahsfh seeemswmmmtwhen? 9811119990 11 1 91981 9 w 1 1 1 1 9 moo ommm9878u8 nylthio urea *Nitrogen rather than chlorine. "Chlorine and bromine in meq./g.

UTILITY The ureas of this invention are, in general, herbicidal in both preand post-emergence applications. For preemergence control of undesirable vegetation these ureas will be applied in herbicidal quantities to the environment, e.g., soil infested with seeds and/or seedlings of such vegetation. Such application will inhibit the growth of or kill the seeds, germinating seeds and seedlings. They are applied directly to the foliage and other plant parts in post-emergence applications. Generally they are effective against weed grasses as well as broadleaved weeds. Some may be selective with respect to type of application and/or type of weed.

Preand post-emergence herbicidal tests on representative ureas of this invention were made using the following methods:

5 representing no phytotoxicity, l00

seedling emergence, health of emerging seedlings, etc., for a 3-week period. At the end of this period the herbicidal effectiveness of the urea was rated based on the physiological observations. A 0 to 100 scale was used; 0 representing complete kill. Post-Emergence Test The test urea was formulated in the same manner as described above for the Pre-Emergence Test. The con- 10 centration of urea in this formulation was 5,000 ppm.

This formulation was uniformly sprayed on 2 replicate pots of 24-day-old test plants (c.a. -25 plants per pot) at a dose of 100 micrograms/cm? After the plants had dried, they were placedin a greenhouse. The plants 15 were watered intermittently at their bases as needed and observed periodically for phytotoxic effects and physiological and morphological responses to the treatment. After 3 weeks, the herbicidal effectiveness of the urea was rated based on these observations. A 0 to 100 scale was used; 0 representing no phytotoxicity, 100

representing complete kill.

The results of these tests appear in Table II. For comparison the structurally related compounds, N-pchlorophenylthio-N-p-chlorophenyl urea, N,N'- dimethyl-N-p-chlorophenylthio urea and N-methy1-N- p-chlorophenylthio urea, were also tested by the above described methods. These test results also appear in Table II.

TABLE II Compound N -2,6'dichlorophenyl-N-methyl-N'-pheny1thio urea N-p-tolyl-N-mcthy1-N-phenylthio urea N-p-tolyl-N-1netliy1-N-p-chlorophenylthio uro N-m'chlorophenyl-N-methyl-N-phenylthio urea N -p-metl1oxyphenyl-N-methyl-N-phenylthio ur N -p-methoxypheny1-N-methyl-N -p-ehlorophenylt N-3,4-dichlorophenyl- '-methyl- '-pheny1thio urea*. N-3,4-dichlorophenyl-Nethyl-Nmhenylthio urea. N -p-ch1orophenyl-N-methyl-N -phenylthio urea N-m-chlorophenylN-methyl-N-p-tolylthio urea N-phenyl-N-p-chlorophenylthio-N-methyl urea N -p-chlorophenyl-N -athy1-N -p-ch1orophenylthio urea N-phenyl-N-methyl-N-p-tolylthi0 urea N-o-chlorophenyl-N-methy1-N-p-ehlorophenylthio urea N-3,4-dich1orophenyl-N-methyl-N p'tolythio urea N-p-chlorophenyl-N-methyl-N-p-to1ylthio urea N -m-chloropheny1-N-p-chlorophenylthio-N-methyl near N -3,4-dichlorophenylN -p-cl11orophenylthio-N-metl1yl urea N -phenyl-N -methyl-N -phenylthio urea N -3,4-dichloropheny1-N -methyl-N-pentaehloroplienylthio urea. N -p-bromophenyl-N-methyl-N -phenylthio urea N -p-bromophenyl-N-n1ethyl-N -p-ch1orophenylthio urea- N-3,5-dich1orophenyl-N-methyl-N-phenylthio urea N -methy1-N -phenylthio-N -o-fluorophenyl urea N-m-trifluoromethylphenyl-N-methy1-N-p-chlorophcnylthio urea N -m-tr1'fluoromethylphenyl-N-methyl-N-p-tolylthio urea N-o-fiuoropheny1-N-methyl-N-p-tert. butylphenylthio urea N -o-toly1-N -methyl-N '-p-chiorophenylthio urea N -o-trifluoromethylphenyl-N-methyl-N-p-chlorophenylthio urea N-3, 5-dichlorophenyl-N-methyl-N-p-chlorophenylthio urea N -o-Iluorophenyl-N -methyl-N-p-ehlorophenylthio urea. N -p-ilnorophouyl-N -inethyl-N-pchlorophenylthio urea.. N-ni-llnorophenyl-N'-motliyl-N-p-chloroplienyltllio urea.

N-2, 4-dlllnorophenyl-N-metl1yl-N'- i-chlorophonylthio urea- I N -2-llnor0-5 trilluorumothylphenyl-Nmethyl-N-p-chlorophonylthio urea 100/100 100/100 100/100 N -3-chloro-4-bromopl1m\yl-N -nmthyl-N-p-cl1lorophenylthio urea N -2-fluoro-4-chlorophenyl-N -1ncthyl-N-p-chlorophenylthio urea N-p-chlorophenylthio-N-p-chlorophenyl urea N-mothyl-N-p-chlorophenylthio urea Concentration was 100 micrograms/ch12 in pro-emergence test. Active in pro-emergence application only on broadleaf weeds. K Effective only in post-emergence application.

0 =Wi1d oats (Arena fatua).

R=Annual ryegrass (Lolium mulziflorum).

C Crabgrass (Digitaria sangumalis) W=Watergrass (Echinochloa crusgalli).

M=Mustard (Brassica arzlensis).

P=Pigweed (Amaranthus retroflezus).

L=Lambsquarter (Chenopodium album).

Herbicidal eflectiveness, pre/post O R C W M P L Comparison tests The exceptional post-emergence herbicidal activity of the ureas-of formulas 2 and 3 above is illustrated by the data appearing in Table III below. These data were developed using the Post-Emergence Test described One of the preferred compounds, N-3-bromo-4- chlorophenyl-N-methyl-N,'-p-chlorophenylthio urea, showed remarkable selectivity between broadleaves and grasses in post-emergence application. For inabove but with the indicated dosages. 5 stance, at a dosage level of 3. 7 micrograms/cm this TABLE III Post-emergence activity-preferred compounds v. analogs 00110., mcg./

Compounds cm. O R W L P M 11 100 100 92 100 100 100 N -p'ch1orophenyl-N-methyl-N-p-ehlorophenylthio urea 3. 7 53 13 58 100 100 100 1. 2 83 100 100 11 100 100 100 100 100 100 N-p-chlorophenyl-N-rnethyl-N'-p-tolylthio urea 3. 7 67 68 75 100 100 100 1. 2 27 60 60 11 76. 7 100 100 100 100 100 N -3,4-dichlorophenyl-N-methyl-N -phenylthi0 urea g 38. 3 71. 7 85 18g 100 11 100 92 100 i 100 100 160 N -3,4-dich1orophenyl-N-methyl-N '-p-toly1thlo urea 3. 7 70 I 100 100 100 1. 2 100 100 100 11 62 100 100 100 100 100 N-3.4-dichloropheny1-N-methyl-N -p-chlorophenylthlo urea 3 72 100 100 100 11 100 100 100 N-o-fiuorophenyl-N-methyl-N-p-chlorophenylthio urea 3. 7 100 100 100 1. 2 100 83 100 Analogs 11 95 97 92 100 100 100 N -phunyl- -methyl-N-p-tolylthlo uren 3. 7 17 17 33 100 100 100 1. 2 7 33 55 11 100 97 95 100 100 100 N -plwnyl-N '-methyl-N-p-chlorophenylthlo urea 3. 7 27 32 37 100 87 100 1. 2 22 17 3 50 N-m-cl1lorophenyl-N'-mothyl-N-p-chlorophenylthlo urea 3 g g g 8 8? N-3,lS-dichlorophenyl-N'-methyl-N-p-chlorophenylthio urea .i g 8 N -p-fluorophenyl-N '-methyl-N-p-chlorophenylthio urea 1% 2g 2g 2g N-m-fluoropheny1-N'-methyl-N-p-chloropheny1thio urea 3g 38 L23 See Table II.

N-3-bromo-4-chlorophenyl compounds are included in the preferred subgenus'of formula 3 above.

The preferred compounds of formula 1 above in which Y is fluorine in position 2 are also generally better than their analogs in pre-emergence applica tions. This superiority is illustrated by the data in Table IV below.

TABLE IV Pre-emergence activity-preferred compounds v. analogs Comm,

meg-l Compound cm. O" W' L P" M 11 100 100 97 100 100 N -o-fiuorophenyl-N-methyl-N -p-chlorophenylthlo urea 95 100 98 18(5) N-methyl-N -pheny1thlo-N-o-fluorophenyl urea 3 3 3g Analogs 11 97 87 100 100 N henyl-N-p-cl1lorophonylthio-N-methy1 urcu 3. 7 67 40 55 100 100 1. 2 50 11 90 89 100 100 N-m-lluoroplienyl-N-methy1-N-p-chlorophenylthlo urea 50 33 40 77 88 7 TABLE IV Continued Pro-emergence activity-preferred compounds v. analogs Np-fluorophenyl-N-p-chlorophenylthio urea 2, 8% g; 82 8g N-o-chlorophenyl-N-methyl-N-p-chlorophenylthio urea a g g g N-phenyl-N-methyl-N-phenylthio urea 3g 3 See Table II.

The data in Table IV show that said compounds of R formula 2 are better pre-emergence herbicides than @NHCN\ their analogs in which the N-phenyl group is unsuby s stituted, the position of the fluorine atom is changed or 1 5 the fluorine atom is replaced with a chlorine atom.

The amount of urea administered will vary with the particular plant part or plant growth medium which is to be contacted, the general location of application, i.e., sheltered areas such as greenhouses as compared to exposed areas such as fields, as well as the desired type of control. For pre-emergent control of most plants dosages in the range of about 0.5 to lbs. per acre will be used. Such administration will give a concentration of about 2 to 80 ppm. urea distributed throughout 0.1 acre-foot. For post-emergence application, such as foliar spray application, compositions containing about 0.5 to 8 lbs. urea per 100 gal. spray will be used. Such application is equivalent to about 0.5 to 20 lbs. urea per acre.

The herbicidal compositions of this invention comprise a herbicidal amount of one or more of the above described ureas intimately admixed with a biologically inert carrier. The carrier may be a liquid diluent such as water or acetone or a solid. The solid may be in the form of dust, powder or granules. These compositions will also usually contain adjuvants such as a wetting or dispersing agent to facilitate their penetration into the plant growth media or plant tissue and generally enhance their effectiveness. These compositions may also contain other pesticides, stabilizers, conditioners, fillers and the like.

As will be evident to those skilled in the art, various modifications on this invention can be made or followed, in the light of the foregoing disclosure and discussion, without departing from the spirit or scope of the disclosure or from the scope of the following claims.

I claim: 1. Urea of the formula:

where R alkyl of one to four carbon atoms, Y is halogen of atomic number 9 to 35, i.e., F, Cl and Br, alkyl of one to four carbon atoms, alkoxy of one to four carbon atoms or trifluoromethyl, with the proviso that when Y is alkyl or alkoxy, said alkyl or alkoxy is in position 2, 4 or 6 of the nucleus, n is 0 or an integer in the range of l and 3 inclusive with the proviso that when n is 2 or 3 at least one Y is halogen, Z is halogen of atomic number 9 to 35 or alkyl of one to four carbon atoms and a is 0, an integer in the range of l and 5 inclusive when Z is halogen, or 1 when Z is alkyl.

2. The urea of claim 1 wherein R is methyl, a is 1, Z is in position 4 of the benzene nucleus and is hydrogen, chlorine or alkyl of one to four carbon atoms and (a) n is l and Y is fluorine in position 2 or chlorine in position 4 or (b) n-is 2 and one Y is chlorine in position 3 and the other Y is chlorine or bromine in position 4.

3. The urea of claim 2 wherein Z is in position 4 and is chlorine.

4. The urea of claim 1 wherein R is methyl, a is 1, Z is chlorine in position 4, n is l and Y is fluorine in position 2.

5. Theurea of claim 1 wherein R is methyl, 0 is 1, Z is in position 4 and is chlorine, n is 2 and one Y is chlorine in position 3 and the other Y is chlorine in position 4.

6. The urea of claim 1 wherein R is methyl, a is I, Z is tert. butyl in position 4, n is l and Y is fluorine in position 2.

7. The urea of claim 1 wherein R is methyl, a is 0, n is 2 and one Y is chlorine in position 4 and the other Y is chlorine in position 3.

8. The urea of claim 1 wherein R is methyl, a is 0, n is l and Y is fluorine in position 2.

9. The urea of claim 1 wherein R is methyl, a is 1, Z is chlorine in position 4, n is 2 and one Y is chlorine in position 3 and the ot her Y is bromine in position 4. 

2. The urea of claim 1 wherein R is methyl, a is 1, Z is in position 4 of the benzene nucleus and is hydrogen, chlorine or alkyl of one to four carbon atoms and (a) n is 1 and Y is fluorine in position 2 or chlorine in position 4 or (b) n is 2 and one Y is chlorine in position 3 and the other Y is chlorine or bromine in position
 4. 3. The urea of claim 2 wherein Z is in position 4 and is chlorine.
 4. The urea of claim 1 wherein R is methyl, a is 1, Z is chlorine in position 4, n is 1 and Y is fluorine in position
 2. 5. The urea of claim 1 wherein R is methyl, a is 1, Z is in position 4 and is chlorine, n is 2 and one Y is chlorine in position 3 and the other Y is chlorine in position
 4. 6. The urea of claim 1 wherein R is methyl, a is 1, Z is tert. butyl in position 4, n is 1 and Y is fluorine in position
 2. 7. The urea of claim 1 wherein R is methyl, a is 0, n is 2 and one Y is chlorine in position 4 and the other Y is chlorine in position
 3. 8. The urea of claim 1 wherein R is methyl, a is 0, n is 1 and Y is fluorine in position
 2. 9. The urea of claim 1 wherein R is methyl, a is 1, Z is chlorine in position 4, n is 2 and one Y is chlorine in position 3 and the other Y is bromine in position
 4. 